Look in here:
http://www.nicoclub.com/FSM/M/2011/
In particular, see page PG-157 in
PG.pdf for battery removal procedure.
Notice that it also refers to EXT-21 (ie, page 21 in
EXT.pdf) to identify the Cowl Top Cover RH, which is the 3-foot long plastic shroud under the RH wiper and which covers the lower part of the windscreen.
Page PG-157 reads:
Removal and Installation
REMOVAL
1. Remove battery cover.
2. Remove cowl top cover (RH). Refer to EXT-21, "Exploded View".
3. Remove cover of battery positive terminal.
4. Loosen battery terminal nuts, and disconnect both battery cables from battery terminals.
CAUTION:
When disconnecting, disconnect the battery cable from the negative terminal first.
5. Remove battery fix frame mounting nuts and battery fix frame.
6. Remove battery.
INSTALLATION
Install in the reverse order of removal.
CAUTION:
When connecting, connect the battery cable to the positive terminal first.
Reset electronic systems as necessary. Refer to GI-65, "ADDITIONAL SERVICE WHEN REMOVING BATTERY NEGATIVE TERMINAL : Required Procedure After Battery Disconnection".