I'm very new to creating stuff, and am trying to learn how to use SimPE so I can make two mods in the future (a playfight interaction for everyone and custom interactions for servos to flirt with electronics). I followed the tutorial about making my first custom interaction to my best ability, but I'm using the linux version of the one by riahmom and things are a bit different here and there. I decided to post it here first in case it is user error (which I'm currently thinking it isn't, but please correct me if I somehow did) and not an oversight.

How would I reorder the bhav "if instance true" thing? Everytime I add one the new thing shows up above the one I made before, instead of below (as it shows in the tutorial). For example, I was supposed to 1. Have the sim move to the painting, 2. Have the sim's fun get maxxed. Then, 3. The sim Dances the hula.
The sim does the hula first, maxxes their fun, then move to the object.
I doubt it's supposed to do this, but knowing how to reorder things like this in the future would be potentially useful so if it is possible I would like to know.

Are you sure you've actually put them in order? They don't always read in order in the BHAV, depending on how you've set up the targets.

Sometimes, they line up a bit better if you click the "Sort" button before you start adding anything (this sorts them roughly after the numbering for True target, and can make the list a bit easier to read). You'll also need to make sure the "true" and "false" target are pointing toward the correct numbers/lines in the "True/False Target" boxes.
(Edited to add: I'm unsure how "sort" works for more complicated mods - I mostly use it for simpler modded objects with fewer targets/lines).

Clicking on any line and adding a line with Ins/True adds a copy that is usually one higher than the previous line (true1/false2 = true2/false3 for the inserted line). If you however haven't sorted the lines, and/or there are true targets with lower numbers further down, those might sort higher and run after the ones you added previously, as the numbers change. I'd think this sorting is why the actions aren't happening in the correct order.

You can add an instance to the middle of the list, or to the end of the list, by first selecting the item you want to place the instance below, then "Ins/True" (or "Ins/false"). They can be moved around or edited if you put them in the wrong spot, but it is a bit easier if you don't have to edit too much. You do also need to make sure they have the right numbers.

Sorting is good to see how it works, however there are some experienced modders who say not to sort as it affects how the game reads and processes the bhavs.

The actual order isn't that important, it's how they target the true/false. If you are simply using the add button it will duplicate the line you have selected and place it at the bottom, however it won't be linked to anything. You can see that by the black line/arrow. You can then link the true/false targets to the right bhav. Or use the Ins/True or Ins/False buttons. This will duplicate the bhav below with the true/false targets linked, you can then edit that bhav as you wish.

There are buttons to move a bhav, next to the sort button, however this doesn't change the true/false targets. Either showing an image of your bhav or sharing the file would help us to better help you link the bhavs.

You can sort actions that will be executed, completed and ended soon after. If you don't sort, you are more likely to make a mistake because the true order of actions is obscured. Consider to keep an existing order in long interactions or function main. Sometimes the script isn't reset when expanded and execution continues from the same line it was left in the previous play session. A reordered script will then have a different action on that line. If you don't sort, you can also see all new additions at the end.

Image added (or I think it's added, it isn't showing up in the preview)
I had tested it out in game to be certain, but I already had an inkling before that it was backwards because of the arrows. Since, as HugeLunatic said, the Bhav's get duplicated when you clicked Add instance, I am realizing that this 100% was my fault. I clicked the wrong one to edit. I've already opened SimPE and tried adding a new link (correctly edited this time), so I'll just redo this little thing again. Thanks guys.

Edit: Got it working properly now. Hurrah!