Do stick to any arrangements you have made. Ask your team leader if in doubt. Do think and pray about your reasons for wanting work on the project. Don't over commit yourself. Offer only as much time as you are able to give regularly.
Reliability is very important.
It is easier to increase the time you work than to cut back once you have committed yourself. Don't keep any anxieties to yourself. Don't give or lend money or presents or receive them. If you think it appropriate to consider making an exception to that policy, discuss the circumstances with your leaders and come to a joint decision as to the best way to respond. Don't carry out a task if you think it unreasonable or for which you feel you don't have the necessary skills.