Hello @lifestylesolutionsbd,

The images that are displayed in the slider section comes from the featured image sections of the particular page/post . So you can upload the image of your choice in the featured image section of the page/post by going to Admin Panel > Page/Post and then to the particular page/post . Here in the right corner your will find the featured image section from where you can upload the image of your choice .

Similarly The text displayed comes from the content sections of the individual post/page so you can input the text as your wish.

Refer to below screen shot for clear info :
http://image.prntscr.com/image/52982d4a363e4f2193773bcd8e2df2a1.png

Hope this helps.

If above information does not clears the confusion, please write back to us .

Best Regards!!