The No. 4 Mk I Lee-Enfield made up the bulk of rifles used by British soldiers during World War II. Here's some background and disassembly tips.
Enfield No.4 Mk1* Long Branch .303 British - Peter J Starley Kft
The No 4, Mk I* Lee-Enfield: Introduction
Exploded View: Lee-Enfield No. 4 Mk I
Lee–Enfield - Wikipedia
Lee Enfield No. 4 MK I rifle by vincentberkan on DeviantArt
Exploded View: Mosin-Nagant Model 1891 Family Of Rifles
Lee–Enfield - Wikipedia
DREYSE 1907 7.65 MM & LEE ENFIELD NO.4 MK.I & 1917 ..LEGEND/EXPLODED VIEW (835Y)
I Have This Old Gun: British Lee-Enfield No. 4 (T) Sniper Rifle
Lee-Enfield No 4 Mk 2 Rifle