Replacing the pistons & seals is a simple job, you just have to be clean and methodical. It's also worth investing in a couple of hose clamps to clamp the flexi brake lines.

FWIW - When pushing the new seals in, I use a little bit of new brake fluid to act as a lube. I then use a wooden ruler to press into place as I find it helps prevent 'nicking' the seal while maintaining an even pressure.

HTH

M