You need to learn to play with the commands. Don't be afraid of doing something wrong.
Look at page 37 of the manual. SPSET is probably the command you need since it talks about activating a sprite. The Format box and others below it tell you exactly what to type to use it.
By "play with it" I mean see which numbers are valid for each thing you have to type after SPSET, and just try the first one of each to see what happens. So just write a program that only says
and watch the results.
Then try to figure out why the thing that happened...happened. Edit your program, try different numbers based on what it says they will do, and run it again. Page 8 in the manual might help too, giving ID numbers for each sprite.
Once you have a handle on that, look at page 38, sprite control, and try some of those commands. SPOFS and SPANIM might be fun.
By the way, in the Format boxes in the manual, if a part of the command is in [brackets], it's optional and you don't have to type it. Otherwise you have to type every part the command is expecting, or you'll get a "missing operand" error.