If your mom is willing to physically help that is step one. Step two a budget. Step three is designing an easy way to expand/improve the coop within budget.
Big box stores like Home depot will make rip cuts for you. That takes a circular saw off the needs list. It also makes things easier to transport.
Even if mom can only help hold things in place while someone else runs screws it's amazing help.
It can be a fun rewarding team effort as long as everyone works together and has patience.
Remember that chickens don't need perfect they need protection from weather and predators. Chickens don't care if it's not square.