Remove the oil bypass line noting carefully the way the red end pieces fit into the third piece. Get this wrong and the oil won't flow.
You should now be left with a case that looks like the picture below. The next step is to undo all the bolts that hold the 2 case halves together. This consists of 8 perimeter bolts (four top and four bottom), Two cam plug nuts which are usually 14mm but are often other sizes and six 15mm acorn nuts.
Start with the perimeter bolts which are found on the top and bottom of the case and undo and remove these. Next find the cam plug nuts which are found at the front (flywheel) end of the engine behind where the flywheel would sit. The cam plug looks a little like a bottle top with 2 nuts holding it (see phgoto below). undo these nuts and keep safe.
Undo the acorn nuts and remove the nuts and special washers that is bevelled to trap the "o" ring seal. One acorn nut is attached to a through bolt so remove the bolt as well. Note early engines used copper washers not "o" rings and also had 2 through bolts. You are now ready to split the case.
The case must never be hit directly with a hammer. Use a piece of timber and gently tap the right half of the case at the top and bottom until it starts to split. DO NOT be tempted to lever it apart. Keep gently tapping and eventually the case will split. As the left side is being held by the engine support the right side will move. As the case splits it should be possible to remove the timing gear and camshaft together. Be careful not to damage them. Ideally the crankshaft should stay in the left side of the case as it splits but this does not always happen. Support the crankshaft carefull as you finally remove the right case half. Once the case half is removed, remove the crankshaft and associated bearings. Also remove the cam plug and keep safe. Remove the tiny pins that hold and guide the bearings. Don`t loose them.
Set the crankshaft and camshaft aside in a clean place. spray with wd 40 if you are not planning to work on the engine for a while.
Thats it - You now have all the bits and you now need to decide what to keep, what to replace.
I would suggest starting by giving everything a good clean.