how to add slider and thumbnails to post ?

Hello outside world 😉

i am currently using anew theme from alxmedia.se

i really like the theme but there is somthing missing, so i would like to hear if it is possible to add a slider on the frontpage like in hueman theme, there is showing resent posts with thumbnail pictures. it could also be cool if my posts had a thumbnail! i have set my featured post image and in hueman theme it works but in anew theme there is no thumbnails images only in the sidebar……