Huawei Honor 3C H30-U10 Quick Start - Manual (Page 4)

Installation
Caution
When you install a micro-SIM card, make sure you do not
mix up the slots of WCDMA and GSM cards. Otherwise
your phone may fail to detect the micro-SIM card.
Follow the instructions in the following figures to complete
the installation. Then press and hold the power button to
power on your phone.
1
2
Open the battery cover.
Insert the micro-SIM cards.