The not cheating way
First you need to have Sims 2 seasons installed, next go into buy mode and purchase a fruit growing tree. When there are bugs have the sim spray them. Then after a lot of spraying your sim will turn into a plant sim. This is really time consuming because bugs only spawn every once in a while.
The cheating way
This way is slightly easier but still pretty time consuming. You need to purchase a fruit tree, then you need to hit the ctrl, shift, c buttons in the cheat bar type boolprop testingcheatsenabled true shift click the tree and hit spawn bugs have your sim spray the tree and repeat until your sim turns into a plant sim
I hope I have helped you in getting a plantsim
After your sim is a plantsim they only have three bars
Sunlight will go down if they are inside and at night you can get a lamp, I don’t remember witch one.
Water Is self explanitory drink water or take a bath and this bar will go up.
And Love is self explanitory also just treat it like a regular sims social bar