How I can install Red Hat 7 in ThinkServer RS140

I assume you mean RHEL 7.
What kind of boot drive do you have, DVD or usb?
Do you want only RHEL7 on this box?
Be aware that RHEL is a paid for distro - includes support and updates.
If you want a free version use Centos7 instead - includes updates but not phone/email support.

HTH & Welcome to LQ

Do you need to find out how to 'burn' (create) a bootable (.iso) Linux dvd/usb?
What's your level of experience? (Do you know how to select a 'bios boot device'?)

Try web-searching (gets instant results)! This search: ThinkServer RS140 linux
finds a bios update, an OS install guide!, & lots more!

Spend some time looking around (&Searching LQ), and the FAQ. Best wishes.
Let us know more specifics.

As mentioned above, RHEL 7 is a distro you pay for. If you check out the Red Hat web site, all the information you need is there; Release notes, Installation notes, etc. Why haven't you checked this out before posting here?

Note that installing a version of Red Hat Linux will mean you will not be able to download and install any updates, security or otherwise without a paid for support contract with Red Hat. Not a good idea if you're going to be running a commercial server.

As mentioned by chrism01, perhaps you should consider Centos 7 which will get you the necessary updates but you'll need to use the community for support instead.

Play Bonny!

Read the "Question Guidelines" link in my posting signature. RHEL on IBM hardware is a fully supported configuration. If you have problems getting things going, you can either contact IBM support or Red Hat support. IBM's website has documentation on how to install various OS'es on that hardware...did you look there?? And this also is going to depend on what controller/disk options you have installed on that IBM hardware. Again, IBM is your best resource.

Doing basic research first before posting is a good step, as is providing details. You don't say what you have done/tried so far, and your question is very vague. Have you contacted Red Hat support, for this installation of RHEL that you've purchased???

step #1 for "red hat 7"
you do not it is from 1995

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for Red Hat Enterprise Linux 7 ( rhel7 )
step #1
contact redhat sales and BUY!!! the required support contract and get the iso from redhat

#2
burn it to dvd or usb ( if usb boot is an option )

#3
install rhel7

#4
REGISTER!!!! your install with redhat and update the os

#5
each year renew the REQUIRED support contract