Main page post – want full article and comments not excerpt

Hello !!

I am using a template called aspiremagazine and have changed some graphics and text colors but onmy main page the template calls for only a snippet of the actual article and a small graphic thumbnail version that is suppsed to generate from an image in the article and also show up at the top of the page in an animated box,

I have two questions about this and I really hope someoe can help me out ; how can I get the full article to show up ( including a YouTube video or any/all pics ) in the post section in the front page , and does anyone know how the post generates the thumbnail and if it goes into sme folder that I am unaware of ? It seems that only some posts will put the thumbnail version in the post and in the featured section .
( ps what is the section of editable code where my posts show up ?.php ?
the blog is located at https://fierth.com/a <must incl ‘a’
Thank you so much for your help !! Brian

I have already selected full post on readng settings

If u know the answer really dumb it down for me lol thanks