If you are just starting with openwrt/lede I really recommend you stick with the stock firmware (do update to the latest on vocore.io) there are two reasons:
1. There isn't that much difference in what you will learn, yes lede stays more up to date and you may want to eventually switch to it when you have learned a bit.
2. The open source wifi driver for the 7628 stinks! You will likely have poor performance (speed) and there is a definite possibility it will be bad enough it is unusable.
If you do decide to switch to
lede now keep these things in mind:
1. Wifi is not enabled when you install lede (or openwrt) with their standard firmware, the lede dev images (the only place to get one for a lite) don't even have the web interface. This means either an Ethernet or a serial connection will be the only way to connect after you install. Make sure you have one of these working or you will have a tiny paperweight after installation.
2. The wireless configurations between the stock wifi driver and the opensource wifi driver are totally incompatible. Make sure you do not keep configurations or settings if you use sysupgrade or the web interface to upgrade. There is a checkbox on the web interface, make sure it is UNchecked if you use this method. For sysupgrade make sure you use the -n option. For a beginner this would be very confusing/difficult to deal with, I'm fairly experienced on lede/openwrt and I do this because of the incompatibilities. If you use the bootloader (das u-boot) this isn't a problem since there isn't a way to keep your settings.
This tells you how to switch with the webinterface.
This tells you how to switch with sysupgrade.
To use the bootloader you need a serial connection and use option 0 on the u-boot menu to upload the image with a kermit client on your host box. The USB/uart converter on the vocore ultimate is slow to start on power up, you may not see the uboot menu. If so, type reboot at the command prompt, the converter will already be going and you will see the full boot process. If you have another variant you need a
USB/uart converter with one of these plug it in to your host box and start a serial console before you power up the vocore.
The people on the
lede/
openwrt forums are very helpful. Remember that no one is getting paid to do this so be polite and patient. "FIX MY BOX NOW!" posts are a very good way to get ignored. No need to worry if english is not your first language, they are used to users from all over the world. They are predominately linux users so "how do I use this windows(or apple) program to do this?" will likely be answered with a wall of silence.