Hi a new member here with some 28DH queries

[Tipper]

  My neighbour gave me a Lister 28DH. It seems to be in good condition, I'm looking for any info about the 28DH, excuse my ignorance but the box with the HT lead for the spark plug is not  in place, I can see where it sits and I have the timing chain, I don't  know how to set it up. Also what oil should I use is 20/50 classic oil ok? engine no. 1/67266   1.5HP.
 Thank you in advance for any help.