If you've never logged into FamilySearch before, create an account. That is done by going to: https://www.familysearch.org/en/, then clicking on the "CREATE ACCOUNT" box at the upper right corner of the page.
If you would like more instructions, click on the question mark in a circle just to the left of the "CREATE ACCOUNT" box. The help box shown here at the left will pop up. Then click the link that says, "How do I create a free FamilySearch account?' That should tell everything you would need to know.
FamilySearch has simplified many instructions for using their tools. To get started go to: https://www.familysearch.org/gettingstarted/ There are several wonderful ideas to get you started. They are also available in the help box shown at the left. Just click the blue circle with the light bulb in it.
The Family History Guide has a great detailed tutorial with information on navigating and using FamilySearch. This is a wonderful place to start. The entire website is well worth exploring. There are many activities, instructions, tips and helps to be found there.
There are tutorials for both the Family Tree App and the Memories App that are available for phones and tablets also at the Family History Guide.
Here is a link to the Church's media site for a 2 minute video on how to add photos to the Memories section of the FamilySearch web page.