>how did he return them all?? was he able to time jump by
>himself??

If you remeber when they went back to 2012 (attack on NYC) him and Tony set their hand device to 1970 and jumped there themselves.

if so, why do they need all that equipment to send
>him off??

He needs the machine to jump into the quantum realm but he can then move around as long as he's got enough Pym particles. Once they brought everyone back that included Hank Pym who could make more for them. Also if you noticed when Cap went back and saw Peggy he knew he'd come back to her and he grabbed extra.

>also, how did old nebula get thanos into the future??? she
>only had one pod right??? so she used it to get to the future
>then ... i didnt understand

She gave the Pym particles to Thanos who reverse engineered it. Thanos is not just super strong he's also a genius. "You're not the only one cursed with knowledge".