Use Anglo-Saxon Old English Futhorc for reading and writing Modern English. It is a phonetic alphabet, so you write words exactly as you speak them and hear them.
A phonetic table which gives the runes modern names and describes their sounds: Phonetic Table of English.
An Anki flash card deck which can help you memorize the letters (runes) and their sounds: flash cards.
This is the basic keyboard layout
It is a phonetic layout to help memorization. The consonants are on the left and the vowels are on the right. Starting at the top left are the libial consonants. The middle row is the alveolar consonants. The bottom row is the velar consonants followed by ᚷ. The column just to the left of the vowels is the post-alveolar consonants and ᚦ. ᛉ is not phonetic, but it can be used for Roman numerals or writing X in acronyms.
The left most column of vowels are the front vowels. The next 4 keys are the back vowels placed in a Z shape. ᚩ is on the bottom and ᛠ is on the right.
Since ᚩ is on the comma key. Use shift+, to get comma. A lot keyboard software has trouble modifying Space key, so the middle dot (word separator) goes on period (low dot). Use shift+. to get period.
If you want to play around with the keyboard layout you can download it and upload it to keyboard-layout-editor.com.
Install HeliBoard and follow these instructions. You may need to install F-Droid (package manager) first.
If you want to continue using another keyboard for non-runic writing, you should be able to use the language button to easily switch between keyboards. In HeliBoard settings, you can set the language button to do exactly this.
Optionally, you can download install a dictionary for spelling correction and word suggestion.
Follow instructions on the git repository.
I have found that the Junicode font is by far the best font for displaying Anglo-Saxon runes.