what county you in .. that will help a lot for us to help ..
you can't do a thing till your ffl03 gets approved and you get your cert .. .. i think the thing is do not sign it .. you make copies of it and sign the copies to give to seller .. do not sign the original one
Agree with @Bullet Guy . Call and check. I know in NY you can not ship a C&R handgun to the license. It has to go to a 01. Here in Georgia you can ship them on your license no problem. Everywhere varies