The present work addresses the problem of a self-consistent-field (SCF) description of a specified polymer melt/solid substrate interfacial system, Key points of the employed method are the coarse-grained representation and the numerical treatment of the continuous-space SCF theory. Compared to other works on polymer adsorption, the main difference of the current approach is the description of the polymer coil connectivity through the wormlike chain model, which, after incorporating local stiffness, reproduces two characteristic lengths of the studied polymer: the mean-squared end-to-end distance and the contour length. As a test case, polyethylene melts adsorbed on a graphite substrate are considered recent atomistic simulations of the same systems are used to evaluate the theoretical approach. For comparison and elucidation of some effects of chain stiffness on conformational properties of adsorbed molecules, an alternative (and more common) representation of chain connectivity through the Gaussian model, reproducing the mean-squared end-to-end distance, is also considered, Results refer to local and global chain conformational properties, with an emphasis on the latter, In particular, predictions for the shape of chains are obtained, while the conformations of adsorbed molecules are quantified in terms of tails, loops, and trains. For small chain lengths, both the Gaussian and the wormlike chain models deviate considerably from the simulation data. At intermediate chain lengths, however (such as C-100), the predictive power of the wormlike model is very good for several conformational properties, On the contrary, predictions from the Gaussian model, especially for the case of loops, deviate considerably from simulations over a broader range of molecular lengths.