How am I suppose to change the fixed ip address without access the antminer config page? Am I suppose to connect it directly to my computer? And my router is 10.154.192.1
You probably cannot see the antminer on your network, as its factory default IP address is 192.168.1.99, which is probably not supported by your router's address range.
Can log into your router's configuration and check what is the address range that it supports, and select 2 unused addresses in that range? Assuming that you found that address 10.154.192.90 and 10.154.192.91 are those address. Now disconnect your computer from the network and setup an 'isolated network' between your PC and 1 antminer.
To do this you would ideally use a 'crossover' Ethernet cable (which usually is red in color). This may not be an absolute must, as many modern PC Ethernet ports would automatically reconfigure to support a normal 'straight' ethernet cable. Your other option is to use an ethernet switch with 2 'normal' Ethernet patch cables (this needs to be an isolated switch which is not connected to the rest of your LAN).
Next you need to disconnect your PC from your LAN and configure the PC which is used for this for a fixed IP address. Assuming that you use Windows 7, this can be done by going into Control Panel\Network and Internet\Network Connections, select your wired LAN adapter, properties, change the IP4 settings from 'obtain an IP address automatically' to 'use the following IP address' and enter something in the 192.168.x.x range, say 192.168.1.2 (this is necessary, so that both the PC and the 'factory reset' Antminer are both at the same subnet).
Connect the LAN cable between the PC and the Antminer and turn the antminer power supply on (assuming that you have a paper-clip or similar arrangement to turn the power supply on).
Now open your web browser and type 192.168.1.99 in the address bar and press 'enter'. If your antminer is at factory default settings, you should now see the web gui login screen in your browser. The default login is 'root' and 'root' as password.
To modify the antminer address settings go to the Network tab,
don't touch the LAN setting, modify the WAN setting by clicking on 'Edit' and then modifying the IPv4 address to your chosen address (in our example it is 10.154.192.90), 'IPv4 gateway' change to your router address, which is as you stated 10.154.192.1 (a rather strange address, hopefully it is correct). For 'Use custom DNS servers' enter again your router's address, or your IP provider's address (you might want to add a second DNS server such as Google 8.8.8.
. Leave all other LAN settings as they are. Click 'save and apply'. Shut down this antminer. Replace it with the second one, except now set it for the second address (10.154.192.91 in our example). When you are done, change the PC lan interface back to DHCP and connect the 2 antminers to your LAN. Now you should be able to see them at the new nominated addresses (10.154.192.90 and 10.154.192.91) in your browser, they should connect to the internet and start mining on the test pools. Change the settings to your pool(s) and start your mining.
Cheers