Please answer in detail. I am having a lot of trouble with understanding this topic. Thank you!

On Dec 31, 2021, DollCo had a debit balance of $1,400 in its' Allowance for Doubtful Accounts. (a) DollCo estimates 9% of its accounts receivable balance of $90,000 will become uncollectible and records the required adjustment to Allowance for Doubtful Accounts. (b) On May 11, 2022, DollCo determined that JOE's account was uncollectible and wrote off $1,200. (c) On June 12, 2022, Joe paid the amount previously written off. Instructions Prepare the journal entries for (a), (b) and (c)