We bought some S5720-52X-PWR-SI and they don't have the command portswitch.

I attached the display version and display patch-information

Huawei Versatile Routing Platform Software
VRP (R) software, Version 5.160 (S5720 V200R008C00SPC500)
Copyright (C) 2000-2015 HUAWEI TECH CO., LTD
HUAWEI S5720-52X-PWR-SI-AC Routing Switch uptime is 0 week, 1 day, 1 hour, 0 minute

ES5D2V52S003 0(Master) : uptime is 0 week, 1 day, 0 hour, 59 minutes
512M bytes DDR Memory
241M bytes FLASH
Pcb      Version :  VER.B
Basic  BootROM  Version : 0208.0001 Compiled at Oct 20 2015, 09:23:09
BootLoad  Version : 0208.0001 Compiled at Oct 29 2015, 21:49:52
CPLD   Version : 010f
Software Version : VRP (R) Software, Version 5.160 (V200R008C00SPC500)
PWR1 information
Pcb      Version : PWR VER.A


************************************************************************
*                The hot patch information, as follows:                *
************************************************************************

Slot       Type           State     Count Time(YYYY-MM-DD HH:MM:SS)
------------------------------------------------------------------------
0          C              Running   12    2016-02-02 08:10-02:00 DST


If the commando portswitch doesn't exist, how can we change the layer 3 ethernet port to assign an IP to use it as a router?

You can see below that the portswitch doesn't exist

[Huawei-GigabitEthernet0/0/1]por?
  port                                    port-auto-sleep
  port-isolate                            port-mirroring
  port-security                           portal

[Huawei-01-GigabitEthernet0/0/1]por