1. Drag the spell icon onto a hotbar, bind it to a keystroke
2. Right click on icon in hotbar, a select enchantment menu will show - choose your enchatment
3. Enchantment will be auto selected in future
If you weren't aware, you can autohide hotbars so they only show if you hover over them. This means you can have a clean screen by hiding simple/memorised macro keys like the one described above.