how to tranform large size assembly format in few steps

Save as

save as type of file, select stp, igs, stl, parasolid

there are some options like save just exterior faces, all bodies etc

hope this helps

Do you want to translate the whole assembly as one file, or just to have all of its components translated to foreign format individually?

Here is an option

Save your assembly as a SW part first, then save this SW part to whatever format such as step file