If you have several turtles on the page and want one of them to follow a command, you will need to make it the 'current' turtle. You can click on it — but, of course, you will need to know how to do that with code.
Here's how to see what turtle or turtles are 'current' now:
show who
t3 t4
If you want to talk to only one turtle, you can type its name followed by a comma and the command:
t1, fd 100
Or you could use the talkto (tto) command to speak to either a single turtle or several turtles
talkto 't1' fd 100
talkto [t1 t2] fd 100
These methods make the turtle(s) you addressed current:
t3, bk 20
show who
t3
talkto [t1 t2] fd 100
show who
t1 t2
-- and all the following commands will be executed by these turtles from now on.
If you want to talk to ALL the turtles use everyone
everyone [fd 100]
Tip: Don't forget the apostrophes and / or the square brackets [ ] !
If you need to just temporarily ask some specific turtle to do a specific job, use ask
ask 't1' [fd 100]
ask [t1 t2] [fd 100]
Tip: Since ask is about a "temporary work", you have to put the list of instructions in the square brackets. Lynx needs to know when to let these temporary workers go!
everyone and ask do not change who is the 'current' turtle.
t3, bk 20
show who
t3
everyone [fd 100]
show who
t3
ask [t1 t2] [rt 45]
show who
t3