Usually the past participle does not change when conjugated with AVOIR but if there is a preceding direct object then the participle has to agree. e.g Les lettres que j’ai reçues.
Les lettre = feminine + plural precede the verb, therefore, past participle also has to feminie + plural.
The Past Historic is a past tense used for recounting past events, usually in novels and stores. Therefore you only need to recognise it, not use it yourself. If you read a French novel as part of your A2 course or for coursework, you will soon get used to it.
|Il/elle fut||ÊTRE to be|
|Il/elle eut||AVOIR to have|
|Il/elle alla||ALLER to go|
|Il/elle fit||FAIRE to do/ make|
|Il/elle reçut||RECEVOIR to receive|
|Il/elle finit||FINIR to finish|