Size of the slider + preview

Hi,

I have few issue to setup what I need for my blog.

1/ I would like to have a home page similar to this one : https://www.helpscout.net/blog/
Basically, one header/slider with 1 post and, my post under it.

When I try to add a slider with one slide, the image is really huge, and it’s not an issue with the image, I have tried to change the featured image of my post, with a smaller one and the image is still huge, but pixelated.

Do you know how to limit the size of it please ?

2/ When I use the Post grid element, it shows me maybe 7/8 lines of my post in preview, on the home page. Do you know how can I limit the amount of line showed or only show the title only ? 

I like the way the posts are shown by Kleo, with 2/3 lines of text and the number of Likes + the little “read more”. It’s possible to use this view when I create my page ? (For now, I can only have this view if I use the “latest posts” as a home page” which is not what I want.

Thanks for your help! I you your support is awesome! 🙂
Sebastien