you can start your family tree however you want.
But generally - yes - you will start with yourself and work both backward (back in time - your ancestors) and forward in time (your descendants).
But realize that for any living persons - such living persons will only be viewable by you. where as deceased persons will be viewable/editable by any user of the system. and chances are most of your ancestors are probably already in FamilySearch.
Dennis answered the question but it might be useful to realize that that is the normal method of starting their tree when a person opens a new account
I think it depends what they meant by "forward"
by "forward" did they mean descendants or ancetsors?
Yea, but in either case they normally start with an entry for themselves. If it is an account for a church member, that has already been done for them.
Terminology is funny. We typically refer to our "Tree" as all of out ancestors, etc.. But would that not make our children the "Roots" of our tree? You think of "Roots" as where something has grown from, so what we are calling our tree should probably be called our "Roots" and those descendants of ours are our "Tree" emerging from our "Roots".
It might help with the old "My Tree" confusion here IF we referred to all of the deceased ancestors in the FSFT as "My Roots" 😁
So moving "Forward" in the tree could be from true roots to branches (i.e., decendancy), but moving "Forward" in a research sense is from me to back in time (i.e., ancestors and their ancestors). But that would be different "roots" to "branches" as well.