Carry out relevant eligibility checks on your new trustee and confirm their appointment. Then give them an induction that will help them thrive in their new role. Boards vary in how they operate so a good induction is useful, even if they have been a trustee before.
Different people will have different needs, so tailor your induction to suit the individual. All board members share the same responsibility so they must all be able to participate on an equal footing. Find out what training and support your new trustees need to carry out their role well. The way your board currently operates might not work for your new trustees. Be willing to make changes to accommodate them and set them up for success.