Lots more helpful info on lead roof flashings here :
This video shows the basic steps in making and fitting lead soakers. Lead soakers installed underneath slates or double lapping plain tiles to create water proofing where a roof abuts a wall or chimney.
After you have installed your lead soakers you may need this video on how to make simple step flashings to cover the upstand of your lead soakers…
If you want to buy some good quality low cost lead bossing tools they can be found via the affiliate links available on my website here : http://www.fixmyroof.co.uk/tools-and-misc/