How to Create a Digital Planner Step-by-Step Like the One in This Etsy Listing

To give a more comprehensive answer — making a project like this is not a simple thing. InDesign is a complex tool with a steep learning curve, and the tasks needed to create something like this, even starting with a template, are considerable. You will really need to work through some basic tutorials and work on some simpler projects before tackling this.

Also — if this is for your own use, it would make a good goal/project to learn InDesign and progress to the needed skill level.

However, if your goal is to create such planners for sale, on Etsy or KDP or elsewhere, know that the market for them is VASTLY overfilled and despite all the tutorials, videos and promoters on social media, no one sells any of these "low content books." The era in which they sold, and may have made good money for a few early participants, is long gone. KDP/Amazon in particular has compartmented these "non books" into their own category that is not promoted, and is very strict about content and format for new items, often rejecting or blocking them and blocking user accounts after too many unsuccessful submissions. Just so you know.

I think it's a duplicate question:

https://community.adobe.com/t5/indesign-discussions/book-cover/m-p/14826012

If you want to learn how to use InDesign - there are plenty of free and paid tutorials. 

Do you know hoe to make book cover like this ?