The channels for receiving orders should be carefully screened. Basically, there is little need to pay a deposit, only some platforms with good reputation and convenient refund. We can consider paying a deposit and bidding.
Before you start editing, you can find some films with similar styles for Party A's reference to see if you can edit according to this idea. It would be better if Party A provided you with samples with similar effects. When conceiving the video, you can also prepare some video outlines, shot-taking scripts and other manuscripts as tools for editing and communication, so that Party A can have a clearer understanding of the video and avoid repeated revisions and waste too much time and energy due to insufficient communication in the later period.