How to stop a facebook friend from viewing your recent activities?

[Flora]

Ok, there's this facebook friend of mine i don't want her to notice im online whenever i am. So as usual i turn the chat off only for her. But the problem is whenever i like or comment on a post she'll find out right away! The other way she finds out id been online is when i log in w my phone and then log out, Facebook shows it! (By displaying a little phone next to my name in the friends to chat list and saying for example 5 mins ago So shell know ive logged out then) So even if i don't have any activities, she'll know ive been online.
How can i stop her from knowing im online? i dont wanna unfriend her. I just dont want her to know.
Please help me!

[Daniel]

Add Her to the Restricted List Once you Have Done That When you Comment Or Like Something She Wont Know Unless She Visits the Persons Profile and Happens to Notice

[Hinata]

Add Her to the Restricted List Once you Have Done That When you Comment Or Like Something She Wont Know Unless She Visits the Persons Profile and Happens to Notice