There are two major approaches.
1. Pre-flash the paper with a very dim light and no negative. It can be done under the enlarger, or with a 5 watt bulb some distance from the paper. The purpose is to put enough light on the paper so that it is just below the threshold. In other words, if developed at this point the paper would remain white, but if exposed to any additional light a slight grey will appear. A simple step test is all that is required. Make note of the light source strength and distance from the paper. Expose in 2 second increments up to about 30 seconds. It is important to remember exactly the maximum exposure. after processing and drying, find the portion which is just darker the white. Count backward from the maximum exposure to determine the exposure of this section. With a fresh piece of paper give it the computed exposure then expose it to the negative for your pre-determined exposure time. you highlights should just begin to have texture.
2. Flashing with the negative still in the enlarger requires some good diffusion material like the old Kodak Diffusion material, or several layers of vellum. The use of this method does take longer to explain than I wish to take here, but it is my preferred method.