Update README.md for spelling, grammar, and clarity

Signed-off-by: Bruxism <38876789+Bruxism@users.noreply.github.com>

Author: Bruxism

applications/luci-app-attendedsysupgrade/README.md

@@ -1,11 +1,15 @@
 # luci-app-attendedsysupgrade
 
-This app allows firmware upgrades of routers while keeping user installed packages.
-To do so the app sends a request to an *Atttended SysUpgrade server* which will
-respond with a custom image, containing all previously installed packages.
+This app adds OpenWrt firmware upgrade and update as well as package update 
+functionality via its web interface.
 
-The process takes per images between 30 seconds and 5 minutes, please be
-patient.
+When activated, this app sends a build request that includes system CPU
+architecture/target and currently installed packages to an 
+*Attended SysUpgrade server* (ASU) which, if available, will then respond 
+with an install-ready custom image that includes firmware and package updates.
+
+The process per image takes between 30 seconds and 5 minutes, and may be down
+for a few days during the build rollouts and peak use following major upgrades.
 
 More information on the backend server and how to host one are available on the
 projects page: https://github.com/openwrt/asu