Sidebar only on specific page

Hi,

I’m currently using the theme sketch and have my portfolio as my homepage.

I am hoping to kickstart my blog (which is on a separate page on my site) in the very near future and want to ensure that it all works smoothly.

Firstly, I want to add a sidebar to this page (as well as the individual posts) I have done this by going to appearance>widgets which has now achieved this. However, the sidebar also displays on all of my other pages (apart from my homepage, which is my portfolio) this is due to the theme that I am running.

How and where do I actually need to go to change these settings so that the sidebar is only included on my blog page and it’s posts?

Another thing I wanted to do was to insert a “read more” into my posts so that on the main blog page only the heading photo appears for each post. I have tried using the read more tag however this doesn’t work and I have also read about inserting this tag into pages which are not the homepage, however I do not understand what they are saying as code is all new to me. Where do I need to go to edit this?

my website is jasminehughes.com
Thank you all in advance!