Ещё текст на русском: Вчера вечером один мой сосед пригласил меня в гости на ужин. (I'm actually confused with this sentence cause I don't know if you wanted to say that one neigbor or neigbors invited you, because you did a really controversial thing, which is using PLURAL after the word ОДИН)
Он и его жена действительно дружелюбны и полезные - this полезные means useful and people don't like to be used, don't they?.

Их квартира находится на четвертом этаже - The sentence is grammatically correct but it's more natural to say - они живут на четвёртом этаже
Мне очень нравятся они. The sentence is okay but as for the example above it would be better to say - Мне они очень нравятся
Когда я вошёл в их дом, я услышал одну красивую музыку. Музыка is uncountable so it's strange to use a count word, which один is, with it. However, мелодия isn't so you could have written - одну красивую мелодию
Когда я вошёл в их дом is okay but it's more natural to say - когда я пришёл к ним or войдя в их дом
И я увидел накрытый стол - We use this phrase to say that the table has food served on it already, literally the covered (with food ) table. Also. you can use this phrase накрыть стол - to put food on the table
Я посидел на/в (в sounds better for me. but на is okay too) кресле. The sentence is okay but the logical sequence of events is broken here, because you said that you entered the house, heard some good music playing and saw a dinner table, but you didn't say a word about how the hell you suddenly ended up in that armchair
Мы пообщались/поговорили на разные темы долго полчаса - общаться на разные темы sounds smoother for me somehow than говорить на разные темы. Also, half an hour isn't long
Потом мы начали есть ужин.
Вся еда была вкусной - еда is uncountable so it doesn't have the plural form. However, you could have used the word блюдо, which is a dish as in meal, for that - все блюда были вкусными
Ужин состоял из супа, салата, мяса и риса - You need the verb there not a present participle
Я наверняка любил всем - I can't make sense of it, what do you mean? That you definitely loved everything or something else?


You're doing great. Just some minor mistakes here and there but everything is understandable except for the last sentence