Abstract: Downhole tool assembly comprises a whipstock engageable with a flow control device. The whipstock comprises a channel. A core is removably mounted in the channel. The flow control device comprises a valve with a shiftable sleeve for selectively directing fluid flow. In a process of drilling and operating a branched well, the whipstock is anchored at a junction in a first well. A second well is drilled from the junction in a direction defined by the work face of the whipstock. After drilling, the core is removed to open the channel in the whipstock. The valve can be set to direct fluid flow to the second well so a fluid pressure can be applied to the second well. The valve can also be set to direct fluid flow through the channel to the first well, so a fluid pressure can be applied to the first well.